Cool game! The mechanics are really nice! I can see this being a longer game too with scrolling levels and maybe some other weapons and enemies. The spikes could perhaps be on other walls and you can go through some dungeon. The orange color palette is my favorite. If you're ever interested in making this a longer game I think it has potenital.
Yes I tried clicking on it to focus it multiple times but it didn't help. Maybe it's just a quirk with Firefox. And that's neat that it's upside down. I didn't notice that. You're welcome about feedback, I saw your request for play testing on Discord and wanted to help you out.
Cool concept and the music is nice. I tried your game in Firefox. First thing I noticed was that space bar seems to move the page down. I figured out that up arrow key also works for jump but someone just reading the game might not figure that out as only spacebar is listed for jump. Also if I selected show only this frame or put the game in fullscreen mode, then everything was fine. I also tried your game with the gamepad. For me it was very sensitive. You might consider increasing the deadzone a little bit.
Also I'm not sure if this intentional or not but on the screen that says, "HOME" NOW FELT A LITTLE DIFFERENT, HOME is spelled as HOWE. Maybe that was intentional but in case it wasn't I'm just pointing it out.
The graphics are so beautiful and the mechanics are really fun. I noticed gamepad has rumble sometimes, and hopefully by the time you release it there will be an option to disable that.
Nice little game! If you're still working on it, it would be nice to be able to use the keyboard instead of the mouse and have an exit game button somewhere.